ES2212518T3 - STAMPED ABSORBENT PAPER SHEET, ITS MANUFACTURING PROCEDURE AND DEVICE FOR THE MANUFACTURE OF THE SAME. - Google Patents

Abstract

The present invention relates to a sheet (1, 2) of absorbent paper, in particular made of cellulose cotton and of a specific surface weight between 10 and 40 g/m2, comprising a first embossed zone such as is provided by embossing between an undeforming cylinder (A12) fitted with protrusions and a cylinder fitted with a resilient cladding (C) in such manner that the sheet (1, 2) comprises on one side in particular frustoconical salients (120, 110) of which the tops are situated substantially in one plane. The salients (110, 120) corresponding to recesses on the opposite side, the sheet being characterized in that the first embossed zone (110) constitutes a background base pattern of which the number of salients of height H1 relative to the plane is greater than 30 per cm2, and in that it comprises at least a second pattern (G) constituted of salient-free zones of which the height H2 relative to the plane is greater than H1. The invention furthermore concerns the manufacture of such a sheet and to apparatus designed to implement the method.

Description

Printed absorbent paper sheet, its manufacturing process and device for manufacturing the same.

The present invention is related to the sector of absorbent papers for sanitary use or domestic, and it refers to a sheet, constituted by the less a sheet stamped and intended primarily for the manufacture of toilet paper, but also for tissues, napkins or cleaning cloths.

In the sanitary paper industry and domestic, is used to manufacture these products a absorbent paper of crepe type and low weight, made of cellulose cotton or a gloved fabric. It takes advantage of the elongation capacity of its structure - which remains provided, for example, by crepe or curly - for stamping the sheet. This operation consists of deforming the sheet by some points in a permanent way and get some bumps on a surface corresponding to the depressions, which are made by the other side.

When it comes to hygiene products, the tendency of recent years has been, in fact, that of make them softer and softer to process your thickness and strength characteristics, especially by a print This print also improves the attraction product optics The stamping operation is brought to effect or on a paper with a high degree of humidity, in the wet part of the papermaking machine, or on paper with a low degree of humidity, that is, a paper in transformation. In In this case, a dry leaf is developed, unwound from a coil supplier from the paper machine. The present Invention refers to dry-transformed paper.

The most widespread motifs or drawings of the stamped are formed by a repetition - made on a geometric base - of elementary bumps with a reduced cross section and a simple geometric shape. A an example for this is described in Patent No. 3 414 459 of the United States, which carries - on a stratified sheet, constituted by a certain number of elementary sheets, which known as sheets a set of tails. The sheets are stamped with a frequency of distribution of the bumps and with a height of them, which are adapted to the embodiment of water absorbent products such as, for example, cleaning cloths. The number of elements is 5 up to 5 per cm2. However, the Applicant hereby invention has developed, especially for toilet papers, some drawings whose number of elements is higher, that is, is of 30 to 80 elements per cm2. These elements have necessarily a very fine elementary surface at the vertex, less than 1 mm2. For the latter embodiments, get an aspect that mimics the presentation of a product textile. An example is disclosed in European Patent No. 426 548. This type of print mainly affects the features related to the thickness of the sheet. the same It represents, however, a limited optical attraction.

In order to improve the optical impact, have proposed some drawings that present a frequency of much smaller distribution in relation to the drawings previously commented - preferably less than 2,000 elements per m2 as well as these have a surface highest individual of the elements, which constitute the drawing. The elements can be inscribed in a polygon from 2 to 6 cm2. An exemplary embodiment is described in the Patent European No. 265 298. According to this Patent, the bumps, which they form these elements, they are of an elongated cross section, while the vertices are of a linear configuration. The curves, drawn in this way, are preferably closed, and they give the elements of the drawing a fluffy appearance. In addition, these elements are relatively spaced each. In this way, large smooth areas are achieved whose Softness is not, therefore, affected by stamping. This set of drawing features helps to confer to the paper some qualities of fluffy and softness, which are perceived by the user. However, and as a counterpart, is limited the impact that this type of drawings exerts on the physical characteristics In particular, it is so that the thickness is Very little altered. It can be found that the Stamping operation performance is quite reduced. It is it is necessary to engrave the cylinders with a relatively deep important to get here any gain in thickness.

In order to combine the advantages of the two models of prints, the Applicant of the present invention had proposed with French Patent Application No. 94 15196, dated December 16, 1994, manufacture a sheet that presents a graphic drawing, composed of protrusions of linear form and combined with a background drawing, consisting of Smaller bumps. The width of the bumps linearly it is comprised between 0.1 and 2 mms., and the same They are relatively spaced from each other. Small ones protrusions, which are normally conical, are located at the rate of at least 30 units per cm2. The background drawing ensures the essentials of the features functional, related to stamping, which are the thickness and, especially, absorption. The high density of background drawing protrusions also facilitates the appearance of a fabric and is pleasing to the eye.

The bumps of the background drawing make the main drawing is highlighted, since they are not easily visible to the naked eye because of the small size, That is necessary for them. Its surface by the vertex is less than 1 mm2. This contrast is the result mostly of the high relationship -of more than 50- between the surface of a graphic drawing element and the surface of a small bulge, as well as the high number of small bumps per unit area.

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However, in the course of manufacturing of a sheet according to this French Patent, the drawing graphic, which is embossed on the cylinder, rests on the Stamping rubber as the background drawing spikes. There, for  consequently, a competition between the two types of stamping. In Special because of its small size, the spikes are clearly more effective in stamping than graphic drawing. From this deduces a weaker definition and marking for this graphic drawing

On the other hand, and due to the truncated conical shape of the bumps, there is a neutral transition zone between the plot drawing and the graphic drawing. This area is about not very precise contours, since they remain determined, as a rule, by the position of the barbs of the selvedge according to a geometric pattern and contours - whose shape It is free- of graphic drawing.

The present invention has the object of provide a sheet of absorbent paper that offers - especially in relation to the latter manufacturing - the advantage of greater definition of the drawings, which one wishes to highlight on the background drawing.

The present invention encompasses a sheet of paper absorbent. Mostly made of cellulose cotton and with a weight between 10 and 40 grs / m2; with a first zone stamped, of the type obtained by a stamping between a non-cylinder deformable, comprising bumps, and a cylinder with a deformable coating, such that said sheet has on an overhang face in a way primarily conical trunk, whose vertices are arranged essentially inside from the same plane and these protrusions corresponding to some depressions made on the opposite side - a first zone pattern that constitutes a background pattern drawing, whose number of projection of height H1 is, with respect to the referred plane, greater than 30 units per cm2, while the aforementioned sheet comprises at least a second drawing, formed by some second areas without projections and provided by the interior of the first stamped area, and whose height H2 is - with respect to the referred to plane-superior to the height H1; this sheet that is characterized by the fact that the average diameter of the discs, which can be recorded within the second areas without protrusions, it is more than twice the average diameter of the discs, which can be recorded between the projections of the background plot area; So as characterized by the fact that the adjoining two second areas without projections are delimited from each other by isolated projections, which constitute an alignment.

A projection is considered to be isolated if the average height H of the leaf area, which surrounds it, is higher  at height H1 of the frame area. In this way, a protrusion of the plot area whose height measured from the sheet, which surrounds, it is precisely from H1.

With surprise it has been found, indeed, that on the face, which has depressions, is say, the face directed towards the user, a graphic drawing on the hatched background highlighted with a sharp contrast when losing this one  height with respect to the bottom. This solution is, in fact, contrary to the solution described in the Patent Application French No. 94 15196, in which the drawing had been defined graph by means of areas of depression and how these They constitute the hatched bottom.

This differs above all from the solution presented. in International Patent Application PCT No. WO 97/48551, in which are based on the preambles of the claims of patents 1) and 7) and which describes a stamping procedure, which employs a stamping cylinder, which comprises a drawing of bumps of small dimensions. In this drawing, they have made some incisions in order to make a second drawing linear.

The absorbent paper sheet can only be  composed of a single thickness or sheet; however, this invention also covers the embodiments in which the sheet consists of several thicknesses of cellulose cotton, whole prints.

The heights H1 and H2 are average values, calculated from a number of measurements statistically relevant.

In a special way, the drawing looks good marked if the deformation of the sheet is sufficient for the height H2 is greater than 1.2 times the height of H1 at the end of the  stamping operation.

According to another feature, it turns out that the average diameter of the discs, which can be recorded within the areas without protrusion of the graphic drawing, is greater than the diameter middle of the discs, which can be recorded between the projections of the weft area, and preferably if the first diameter is larger twice - and especially three times - the second diameter.

There is talk that the disc can burn within a given part of a surface if it can be placed at inside of it and is in contact with three projections, which they are part of the edge of this surface part.

In accordance with another feature of the present  invention, so the vertices of the isolated projections are of the same dimensions as the vertices of the projections of the first zone.

Indeed, this special form of arrangement It offers the advantage of a larger unit of the drawing and increases the effect of a contrast, considering that the bumps of the stamping cylinder, which are small ones dimensions, concentrate tensions and exert a more marked pronounced on the sheet at the time of stamping. Finally, Engraving is easier than if protuberances were of different dimensions. It can Use a single tool.

According to another feature of the present invention is so the areas without protrusion of the second drawing They have at least a part of calendered surface. East calendering results from the action of the rubber cylinder, which support at the bottom of the engraving. There is then a smoothing of the surface by the suppression of the rough edges. Calendering improves softness especially since this part is sufficiently Great to favor the touch. For this reason, the part of calendered surface preferably has an extension of at minus 1 cm2, essentially corresponding to the skin part from the end of a finger that comes into contact with the blade when it is held The same with the hand.

According to another characteristic of this invention, it turns out that the absorbent paper sheet comprises two sheets, of which at least one is of the so-called sheets absorbents The latter are assembled together, one by on top of the other and with the protrusions inside the structure. The way to join two of these sheets together can be any such as, for example, knurling or gluing. This last form also includes a type gluing "hotmelt" (hot melt) or cold with, for example, a PVA type tail. The sheets can be perfectly sealed the one with respect to the other so that the graphic motives do not match each other and thus obtain a partial association between sheets In this way, the union between them can be modulated and make the sheet stiffer or softer depending on the number of  junction areas point by point, which are allowed to exist. Finally, the sheets may have graphic motifs. different.

The present invention also encompasses a machine as well as a procedure, which allow the manufacture of a sheet according to this invention.

The machine is characterized by the fact that it comprises at least one non-deformable cylinder, which It has a first zone with at least 30 bumps -in especially in a truncated cone shape- per cm2, and has at least minus two second areas of the drawing or graphic motif -no included here- and whose depth with respect to the side of the vertices of the bumps is at least equal to the depth of the first zone; the average diameter of the discs, that can record within the second zone, is higher than average diameter of the discs that can burn inside the first zone, and the two second zones of the graphic motif are adjacent and separated from each other by isolated bumps, which They constitute an alignment.

According to another feature of the present invention, it is thus that the machine comprises a cylinder of resilient coating and capable of working together with said non-deformable cylinder, and whose properties of resilience are such that, during operation, that material resilient can come into contact with the background of the second areas, but without coming into contact with the bottom of the first zones.

The procedure for manufacturing such sheet consists of stamping the sheet by means of the cylinders of resilient coating and apply sufficient pressure to that the deformation of the leaf within the area of the graphic motif drive - taking into account the elastic recovery of the paper - to a final height that is locally greater than the height of the area hatched

In this way, the solution according to the present invention for combined plot and reserve drawing, allows suppress the functional overload related to the graphic motif according to the prior art. It is done primarily a most important deformation at the level of the barbed edges of the graphic motif, which is translated into a more pronounced marking within this area This results in a better contrast of the drawing. This more pronounced marking also resists crushing. partial that can occur, for example, in the course of sheet winding after stamping operation.

Next, the present invention is described in more detail and with reference to the attached drawings, in which:

Figure 1 shows a top view of a sheet example:

Figure 2 indicates - on a magnification scale - the view of the sheet in Figure 1, in perspective and with a section cross section along the line A-A;

Figure 3 shows the example of a form of manufacture of the present invention;

Figure 4 indicates - on a magnification scale - the view of the sheet according to Figure 3, in perspective and with a section cross section along the line B-B;

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Figure 5 shows a stamping installation for manufacturing the product of the present.

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Figure 6 indicates, schematically, a way for stamping according to the previous state of the technique.

Figure 7 shows, schematically, a example of the manner of a pattern according to the present invention; while,

Figures 8a and 8b represent two photographs of cross sections, made in samples according to the present invention

The sheet indicated in Figure 1 and 2, is composed of two overlapping sheets, 10 and 20, each of which is made, for example, of a curly cellulose cotton and with a grammage between 10 grs / m2 and 40 grs / m2. The two sheets have been stamped separately and are assembled together to constitute a double sheet. The outer faces of the two sheets they form the outer faces of the double sheet.

Figure 1 indicates a view from above, and each  point represents a depression or cavity on the surface of the sheet. These depressions are in the form of craters, and the same They have been obtained by stamping operation. In this way, to each depression on one side of the sheets, 10 and 20, you corresponds a protuberance or a projection on the other side. In the Figure 2, you can see the sheet in perspective view from of a section made according to line A-A of the Figure 1. The projections, 110 and 120, are located inside of the structure, vertex against vertex. According to the example here represented, the two folds are identical to each other. These projections have a truncated conical shape, and the section thereof -parallel to the surface of the sheet- is circular. Is section can also be oval, polygonal or other mode. Instead of simply being conical, the configuration of  They can also be more complex. This configuration it can have, for example, a conical part and a part cylindrical The drawing in Figure 2 shows a particular case, with a perfect match between the projections. In practice, different steps may be provided, at least in one direction to induce a offset between the drawings and obtain thus a partial association. Said in other words, in this case It is so that all outgoing do not form a link between each other, but some are free, at least partially. Therefore, The protrusions are not in the position point by point. In this way, a contact is obtained between a point and the background.

For each sheet you can distinguish a first patterned area, or background pattern drawing T, of a defined thickness H1. The thickness of this area is measured by the difference of one level between the plane of the outer face of the sheet and the plane of P reference, defined by the vertices of the projections, 110 and 120. According to the embodiment shown in these Figures, on each of the sheets, 10 and 20, are planned -by the inside this first zone, which forms the background plot - about second zones that constitute the graphic motif or drawing G. Each second zone G1, G2, etc., etc., is delimited by the projections from the first zone. These are the selvedge, 110L and 120L.  Another second zone with absence of projections is characterized by a thickness H2. As for the weft zone, the thickness H2 of this area is measured by the difference in height between it P plane and the tangent plane on the outer face of the sheet and within this area, in parallel to the plane P. According to the sheet structure of the present invention, the thickness H2 is greater than the thickness H1. With surprise it has been found effectively that the contrast between the graphic motif and the drawing in the background could have occurred because of a difference in the level between these two zones. In order to achieve an effect of satisfactory contrast between drawings G and T, the proportion between H2 and H1 is, in a convenient way, greater than 1.2 (H2 is higher by at least 20% than H1). In addition, this proportion is elevates better than contrast. The 110L projections, called edge protrusions or edge depressions as one considers the outer face or inner face, have a shape that unlike the shape of the other projections of the plot area, which contributes to a more pronounced border marking between the zones, G and T. Indeed, because of the difference in level between the external planes of G and T, the wall of the edge depressions presents an extension of the side of the adjoining area G. This results in an optical contrast effect. It has been observed that it is sufficient that this level difference It exists after the stamping operation. Indeed, with surprise has been found that the effect of contrast it persisted even after some crushing of the structure, which was due, for example, to the winding of the sheet.

In order to give the leaf the appearance of a  fabric, a print density is chosen for the weft area greater than 30 projections per cm 2 and, preferably, greater than 60 projections per cm2. Below a density of 30 projections, the separation between the projections is made relatively important and therefore produces the effect of a network, but not the effect of a background plot.

The graphic motif may consist of discrete elements arranged on the sheet according to a reason repetitive, as this is represented in these Figures. From preferably, the average diameter of the engraving discs is at least twice - especially five times - greater than the average diameter of a disc, which you can burn between the projections of the plot area.

According to one embodiment, which here has not if indicated, the graphic motive is constituted by a motive or continuous drawing as, for example, by a grid. In this case, the width of the area between two rows of depressions of selvedge should not be too narrow in order to ensure the formation of a level difference between the plot area and the Grid. Also the smallest disc, which you can record by The interior of the graphic area should preferably be a diameter at least equal to twice the diameter of a disk which can be recorded inside the graphic area, must be, of preferably, with a diameter at least twice the diameter of a disc that can burn between the projections of the plot area

A shape is represented in Figures 3 and 4 of embodiment of the present invention, in which each element of the graphic motif is composed of two or more second zones G'1, G'2, G'3, G'4, G'5, ..., adjacent to each other for this mode form a third zone G '. For this purpose, the two zones adjoining, G1 and G2, are separated from each other by the 210S insulated projections, which constitute an alignment, preferably single type. Also preferably it is like that that these projections have - by their vertices - a diameter that is not different from the diameter of the plot area and, in particular, the distance, which separates the protrusions from each other within this alignment, corresponds to the passage of the plot area G. This alignment or these supplementary alignments tend to fine tune and to reinforce the definition of the graphic motif. You get a result satisfactory for not differentiating here from the definition of the plot. It can be seen that this effect of highlighting, produced by the alignment of the insulated projections results from the greatest relative depth of these depressions with respect to depressions of the plot area. This is due to the fact that these vertices of the bumps are at the same level of the others.

In Figure 5 a machine has been indicated transformation of cellulose cotton for the production of, by example, a toilet paper. This machine comprises two units of stamped, each formed by an A1 and A2 cylinder, respectively, non-deformable and made, for example of steel, the which are provided with protuberances; as well as formed by cylinders, C1 and C2, respectively, with a coating resilient, such as rubber. Two sheets, 1 and 2, from a cellulose cotton feed coil, are joined individually by the stamping intervals of a unit, A1 and C1, as well as A2 and C2, to be joined together by passing between the cylinders, A1 and A2, which rotate the one above on the other, in order to constitute a single sheet of two sheets According to the example indicated here, the arrangement is of the type of points; on points however, they can also be provided other forms of arrangement such as a lace Between the bumps. On the other hand, you can also join the two sheets together using a glue or mechanically through, for example, a knurling.

To be adapted to each other the shape of the protrusions, the sheets deform depending on the appearance the protrusions of a truncated cone on the face, which enters contact with the rubber cylinder, and if the depressions in the form of crater on the face of the sheet, which It is in contact with the rigid cylinder. The present The invention also relates to a form for stamping the sheets

In Figure 6 the deformation of a sheet of cellulose cotton, produced in the course of the stamping operation according to the prior art. The pressure exerted by the rubber cylinder C and the properties elastic material, which forms the lining of the cylinder, determine, for a given graphic motive, the depth of Penetration of this into the interior of the engraving. This figure it represents above all, in a schematic way, the deformation produced on a sheet of cellulose cotton for a drawing according to French Patent Application No. 9415196. This Figure indicates a section view - taken along the axis of rotation of the cylinders in the contact area between a rubber cylinder C and steel cylinder A with sheet F placed between the two. The cylinder A is provided with small protrusions P1, which they constitute a plot pattern, as well as P2 protuberances, which are in relief with respect to the first. Due of a narrow spacing between the bumps, the Rubber cannot penetrate to the bottom of the engraving. A competition between the protrusions of the graphic motif, for a side, and of the protrusions P1 of the bottom, on the other side. These The latter are more effective for stamping, and motif marking  graphic is little done.

In accordance with the present invention, for the stamping cylinder are chosen protrusions that can define well the first zones and the second zones.

A first zone called the frame area of bottom, it is formed by at least 30 bumps per cm2. These bumps are essentially conical in shape; however, they can also have a truncated conical shape by its base and a cylindrical shape towards its vertex. The section It can be circular, oval, polygonal or otherwise. The height it must be sufficient to allow the deformation of the rubber Around each spike. However, this deformation is limited. due to the characteristics of the rubber used as well as the  separation between the spikes. This spacing, like the surface of them by the vertex - which is of the order of about mm2 - are determined by a relatively density elevated, which aims to give this area an aspect of plot.

A second zone is defined, which does not include the spikes The extension of this area is also sufficient as to allow the penetration of rubber - under the conditions normal operation - at a depth greater than depth of a first zone. In practice and for a cylinder of rubber coating, the material of which is, for example, a hardness of 45 Shore A, the extension of a second zone is of such way, that the average diameter of the discs, which can burn by the interior of this area, be twice the diameter of the discs, which can burn between three bumps in the area of adjoining plot.

In a simple way, these areas can be provided by uniformly engraving or machining a cylinder according to the plot drawing, before constituting the first zones, and for suppressing by means of a mechanized the present spikes within the second zones, to be chosen.

In Figure 7 they are indicated, in a view of section, an engraving according to the present invention as well as the deformation produced on a cellulose cotton sheet during its print.

On the surface of the cylinder, you can distinguish two first T zones, separated from each other by a second zone G. The blade is deformed by the action of the pressure exerted by the rubber cylinder. It can be seen, however, that The rubber does not exactly follow the profile of the engraving. How consequence of the reduced spacing between the spikes, the rubber I could not reach the bottom within these T zones. Thus, the rubber reaches a depth Hg, which is less than depth of engraving and that is a function of the available space between tines as well as the applied load, which can be characterized by an Rp yield (Rp is less than 1). In addition, cotton It has cellulose due to its crepe shape - certain ability to recovery after removing the tension exerted by the cylinder of rubber. This elastic recovery is characterized by a Rt yield less than 1. It is deduced that the thickness end of the sheet within the plot area T can be expressed by the ratio of Et = Hg * Rp * Rt.

Within the graphic area G, a enough space to allow the rubber to deform by The whole height of the engraving. Considering the same elastic recovery of the paper, the value of the thickness within the zone G can be expressed by the ratio of Eg = Hg * Rt. Of this mode, the product presents, once stamped, first areas and second areas with different heights, measured with with respect to the plane of the vertices of the protuberances.

In addition to the level difference, this is also Stamping way leads to a more pronounced marking of the selvedge protrusions L, given that the leaf experience in this place a more important deformation than around the plot barbs. This difference contributes to reinforcement of the contrast effect between zones T and G.

According to a special embodiment, it is chosen a sufficient extension for the second zone, thereby that it can allow the rubber to rest on the surface  From the bottom. This part of the sheet now experiences an effect of calendering and smoothing.

According to another embodiment and to vary the  drawings, two or more second zones are grouped together. Two adjoining second zones are now separated from each other down a row of isolated spikes. In this case, it can be verified that the bulge line, which separates two zones from each other second, it also has a very pronounced marking.

essays

Some samples, B1 and B2, of the product from engraved plates according to the motives graphs indicated in Figures 1 and 3, and some cuts, which are represented in Figures 8a and 8b. In the Figure 8a, the first background area can be clearly distinguished T and the second zone G, with different levels and with a projection selvedge 110L; Figure 8b also shows a 210S insulated projection.

A B3 sample with a drawing that represents a grid, whose maximum width of the second zone was equal to twice the diameter of the discs, which they can record within the adjacent plot area, ensuring also that the rubber always touch the bottom of the engraving. In the sample the height has been measured in several places from one photograph and with an increase factor of 56. The average values They are indicated below in mms. About photography

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It can be verified that a significant ratio of G / T heights for drawings B1 and B2. Indeed, a difference of average values from 7 to 8 times greater than the distance type statistically allows the conclusion that it is significant, and not the effect of a process random.

However, even with a drawing whose spacing inland of zone G is smaller, it get a ratio of at least 1.2 when proceeding from such so that sufficient penetration of the rubber is ensured within this area

Claims (10)

1. Sheet of absorbent paper, especially made of a cellulose cotton and with a weight between 10 and 40 grs / m2; with a first stamped zone (T), of the type obtained by a stamping between a non-deformable cylinder, which comprises protrusions, and a cylinder of a deformable coating, such that said sheet has -on a protrusion face (110 , 120) in an essentially truncated conical shape, whose vertices are arranged mainly within the same plane (P), and these projections corresponding to depressions made on the opposite side - the first patterned area (T), which constitutes a weft pattern in the background, whose number of projections, with a height H1 with respect to said plane (P), is greater than 30 units per cm2, while said sheet comprises at least a second drawing (G), formed for at least two second zones (G'1, G'2, with a height H2 - without protrusions and provided by the interior of the first stamped area (G) - the height H2 being, with respect to the mentioned plane (P), greater than H1; this sheet which is characterized p Orque the average diameter of the discs, which can be recorded within the second areas without protrusions (G'l, G'2, ...), is more than twice the average diameter of the discs, which can be recorded between the projections of the bottom frame area (T); as well as characterized in that the two second zones (G ', 1, G'2, ...) are adjacent and are delimited from each other by isolated projections (210S), which constitute an alignment. 2. Sheet of absorbent paper according to claim 1) and characterized in that the height of a second area without projections is such that H2> 1.2 * H1. 3. Sheet of absorbent paper according to the preceding claim and characterized in that the vertices of the insulated projections (210S) are of the same measure as the vertices of the projections (110, 120) of the first zone. 4. Sheet of absorbent paper according to one of the preceding claims and characterized in that a second area has at least a part of calendered surface. 5. Sheet of absorbent paper characterized in that it comprises two sheets of which one is covered by at least one of the preceding claims, and these sheets are joined together in such a way that the projections are located inside the structure . 6. Sheet of absorbent paper according to the preceding claim and characterized in that the two sheets are partially joined together. 7. Machine for manufacturing a sheet according to one of the preceding claims, which comprises at least one non-deformable cylinder (A1, A2), having a first zone (T) with at least 30 protrusions per cm ^ {2}, and has at least two second zones (G) without protuberances and whose depth, with respect to the height of the vertices of the protuberances, is at least equal to the depth of the first machine zone which is characterized because the average diameter of the discs, which can be engraved within the second zones, is greater than the average diameter of the discs, which can be recorded within the first zone; as well as characterized in that the two second zones are adjacent and are separated from each other by isolated protuberances, which constitute an alignment. 8. Machine for manufacturing a sheet according to claim 7) and characterized in that the machine comprises a cylinder with a resilient coating and capable of acting in conjunction with said non-deformable cylinder, and the resilience properties thereof are of such so that, during operation, the resilient material can come into contact with the bottom of the second zones, without thereby coming into contact with the bottom of the first zones. 9. Procedure for stamping an absorbent sheet, especially made of cellulose cotton and with a weight between 10 and 40 grs / m2, between a non-deformable cylinder - provided with protrusions distributed in such a way that a first zone be constituted, which represents a background pattern drawing with at least 30 protuberances per cm2, and at least two second zones, without protuberances, adjacent and separated from each other by isolated protrusions, which they form an alignment - as well as another cylinder with a resilient coating; This procedure is characterized in that - being the average diameter of the discs, which can be recorded within the second zones twice as large as the average diameter of the discs, which can be recorded within the first zone - the procedure consists in making penetrate the rubber into the engraving of the first zone, to a first depth, and make the rubber penetrate into the second zone to a greater depth, such that the remaining height of said sheet has a higher height within the second zone and in relation to the first zone.

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10. Method for manufacturing a sheet according to claim 9) and characterized in that the resilient coating is deformed by a depth sufficient for the sheet to come into contact with the bottom of the engraving of the second zone.